What's the most accurate way to measure body fat? One writer took it on herself to check them all

Photograph by: Lorraine Hjalte
, Postmedia News

One day in February, after using a caliper to pinch skinfolds in seven places on my body, my fitness trainer told me how fat I was.

Rather, my body fat percentage. I was not pleased and wondered if I should give up all hope, go home and order two large pizzas. It wasn’t that the number was bad (I was still in “athletic” standing); my concern was that it had jumped roughly four percent since the same time last year.

“But I feel more fit this year,” I told him. “Don’t worry,” he said. “Someone else measured you last year and there can be variance, depending on how aggressive he was in pinching the skin folds.”

This is how my mission to find out just how fat I really was – or how lean, depending on how you look at it – began.

Measuring body fat, otherwise known as body composition, is an increasingly common practice. Whereas the Body Mass Index is a quick estimate that uses height and weight to determine where someone falls on a range of health, from underweight to obese, experts say BMI can be too simplistic. Body-fat measurements, on the other hand, are more accurate because they differentiate between muscle and fat mass.

There are, however, many ways to measure body fat – some more accessible to Calgarians than others – and as my earlier experience showed, there can be much variance in the way it is measured.

So I decided I would try all of the different methods. In one day. No messing around. Let’s get to the bottom of the body-fat question.

Women typically carry more body fat than men; according to the American Council on Exercise. Ten to 13 per cent is considered the minimum for a healthy woman while it’s two to five per cent for men. On the upper end, body fat greater than 32 per cent in women and 25 per cent in men is considered “obese” territory, increasing your risk for disease and other problems.

I wanted to know how much variance each technique had, so I knew I needed a baseline measurement. . For this, I went with the “gold standard” test in fat land: dual energy x-ray absorptiometry (DEXA), a test I received at the University of Calgary. The test is not available to the generable public, but Nancy Scholz, exercise physiologist at the Human Performance Lab at the U of C’s Faculty of Kinesiology, kindly offered to administer the test for the sake of this article. Not only does a DEXA test tell you your weight and fat/lean mass, but it indicates bone mineral content, bone mineral density and more.

Because DEXA testing is not as common as the others, I decided to have the test and then compare the results with those of the accessible options to everyone in the city. (I’d already decided that whichever method gave me the lowest body fat would – obviously! – be the most accurate.) As a baseline, DEXA determined my body fat percentage was 18.6

My experiment began on a sunny day in early May, with test No. 1 at 7:15 a.m. I’d signed up for a Bod Pod analysis at 2110 Fitness (2110fitness.com, 403-252-2225, 6624 Centre Street S.E.). Gym co-owner Jonathan Campbell explained how a Bod Pod operates on a concept similar to underwater testing, which was considered the “gold standard” test for years: volume displacement. The Bod Pod uses air displacement, not water, to calculate your lean and fat mass. For fun, I asked him to guess my body-fat percentage before I stepped into the Bod Pod, outfitted in my swimsuit and bathing cap. (Poor guy.) “I’d guess you’re 24 to 26 per cent,” he said. When I stepped out roughly five minutes later, with an official weight of 132.8 pounds and a body-fat percentage of 18.1, he was surprised. “You’re a lot leaner than I thought,” he said. (Gee, thanks?) At 18.1 pe rcent, I’d snuck into the “ultra lean” category in Bod Pod results, with “fat levels sometimes found in elite athletes.” Hoorah. “You should be extremely happy,” said Campbell. “Whatever your fitness goals are, you can accomplish them.”

Next up, three caliper tests performed by two people: Darren Snell, a fitness trainer in Calgary, and Ken Andrukow, head coach and owner of Reebok Crossfit Ramsay (reebokcrossfitramsay.com, 403-457-4010, #2030 – 2600 Portland Street S.E.). Caliper testing measures subcutaneous fat, typically in seven spots on the body, such as your triceps, abdomen and quadriceps. I’d asked Snell to use two different calipers to “pinch” me – Slim Guide, a common tool, and another, high-end device called the Harpenden – to see if there was a difference between tools. Andrukow used a Harpenden, allowing me to compare results between two testers. My results ranged from 16.3 to 19.1 percent. As we’d all suspected, the greatest variance was between testers, not the type of caliper used.

This was all well and good (I was especially liking that 16.3 percent number), but I needed to know how the results compared to DEXA. When Nancy Scholz, exercise physiologist at the Human Performance Lab at the University of Calgary’s Faculty of kinesiology, administered the quick and painless scan, I had my answer. Measured against DEXA, the Bod Pod was the second most accurate of all the tests. The ranking stood even after Scholz threw in one more test for fun – the Bioelectrical Impedence Analysis, which involved standing on a regular-looking scale. The results were my least favourite: 20 per cent body fat.

To put all results into perspective, my body fat ranged from 22 pounds at the lowest end to 27 pounds at the highest. The results were consistent, in that every test categorized me as “athletic.” That’s good news, as I exercise often and eat healthily. In the future, if I were serious about knowing my precise body fat percentage, I’d opt for a Bod Pod test. Otherwise, I’d stick to a caliper test, which is offered at most gyms.

Body fat testing isn’t a necessity, though. Experts such as Scholz and Snell say that, for a good idea of overall health, you can use simple indicators, such as the waist-hip ratio, blood pressure, abdominal girth and cardiovascular fitness. Those who may want to have their body fat measured, says Snell, are people on a health regimen, or who are training to reach a fitness goal or who, like me, are just curious. If that sounds like you, consider having a Bod Pod test, which is available at 2110 Fitness for $75, or a standard caliper test. If you opt for a caliper test, ask the person who’s going to be pinching you if they’re certified and how many people they’ve tested, suggests Scholz. The ideal answer is, “Yes and more than 100.” And my own suggestion: don’t ask them to guess your body fat beforehand. That’s just mean.

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